[Hallicrafters] SX-117 VFO Alignment

[Koehl_House]

Darrel:
Would you please expound on your statement that you "...cannot get the dial
to calibrate...". Exactly what do you mean by calibration? Calibration
depends upon the adjustment of both L16 and C15F. Getting these right can be
frustrating.
This VFO only tunes 500 kHz. I would be looking for an off-value component
before I started bending plates.

I own two such receivers and calibration on both is well within the reach of
C38, the front panel CAL RESET. Adjustment is only plus or minus 20% of
"mid-mesh" for this control when changing bands and can generally be left
alone when QSYing in-band.

I will note a discrepancy between both of these units and the factory
manual. C15F is shown as an integral part of the tuning capacitor (closest
to the front panel) in the manual. On both receivers this capacitor is/was a
5-25 pf, NPO, ceramic trimmer. The compression trimmer is totally absent and
it appears as if it was never installed...ever. Further, on one of receivers
I found it necessary to change that trimmer to an air-variable (very small
EFJ-type). For whatever reason, it was quite sensitive to temperature
changes and located in an area prone to draft. The receiver was quite drifty
and never actually settled down. Both receivers now are rock solid (10s of
cycles/hour) after warm-up.

73,
Dick K9FFK

 -----Original Message-----
 From: hallicrafters-admin at mailman.qth.net
 [mailto:hallicrafters-admin at mailman.qth.net]On Behalf Of darrel nichols
 Sent: Sunday, October 20, 2002 12:16 PM
 To: hallicrafters at mailman.qth.net
 Subject: [Hallicrafters] SX-117 VFO Alignment


 I cannot get the dial to calibrate in spite of considerable effort...

 Decided I will have to stake the tuning cap, but there are no slots.
 Before I rip the thing outta there and take a hacksaw to the plates,
 does anybody have any ideas, hints, tricks or otherwise.

 Also, the plates are straight on the tuning cap, but there appear
 to be small wrinkles in the copper surface.  Were they staked in
 production?   Perhaps the previous owner straightened the
 bent parts!?!

 Darrel, N0DBX
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